Metropolitan Institute of Technology
Tulua, Colombia
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Rodriguez O.,University of Antioquia | Benavides R.H.,Metropolitan Institute of Technology | Ponce W.A.,University of Antioquia | Rojas E.,University of Antioquia
Physical Review D | Year: 2017

By considering the 3-3-1 and the left-right symmetric models as low-energy effective theories of the SU(3)C - SU(3)L - SU(3)R (for short [SU(3)]3) gauge group, alternative versions of these models are found. The new neutral gauge bosons of the universal 3-3-1 model and its flipped versions are presented; also, the left-right symmetric model and its flipped variants are studied. Our analysis shows that there are two flipped versions of the universal 3-3-1 model, with the particularity that both of them have the same weak charges. For the left-right symmetric model, we also found two flipped versions; one of them is new in the literature and, unlike those of the 3-3-1, requires a dedicated study of its electroweak properties. For all the models analyzed, the couplings of the Z′ bosons to the standard model fermions are reported. The explicit form of the null space of the vector boson mass matrix for an arbitrary Higgs tensor and gauge group is also presented. In the general framework of the [SU(3)]3 gauge group, and by using the LHC experimental results and EW precision data, limits on the Z′ mass and the mixing angle between Z and the new gauge bosons Z′ are obtained. The general results call for very small mixing angles in the range 10-3 radians and MZ′>2.5 TeV. © 2017 American Physical Society.

Vitamin C has excellent antioxidant properties and its use in topical formulations brings many benefits to the skin. For these reasons and the strong global trend to develop natural products base, the industry uses fruit pulps rich in this component for the development of products for the care and welfare of the skin. This article focuses on determining the Hansen Parameters of this vitamin, which are found by the use of group contribution methods then compare them with the same parameters of solvents or mixtures thereof and so, it could estimate numerically which or what would be the best solvents for extraction of the organic compound of a biomass and/or for incorporation into pharmaceutical, cosmeceutical, cosmetic formulations, among others. © The author; licensee Universidad Nacional de Colombia.

Hyperspectral remote sensors acquire data coming from hundreds of narrow bands through the electromagnetic spectrum; this allows the terrestrial and maritime surfaces to be characterized for Earth observation. Hyperspectral image processing requires algorithms that combine spatial and spectral information. One way to take full advantage of spatial-spectral data within hyperspectral imagery is to use multiscale representations. A multiscale representation generates a family of images were fine details are systematically removed. This paper compares two multiscale representation approaches in order to improve the classification of hyperspectral imagery. The first approach is based on nonlinear diffusion, which obtains a multiscale representation by successive filtering. The second is based on binary partition tree, an approach inspired in region growing. The comparison is performed using a real hyperspectral image and a supper vector machine classifier. Both representation approaches allowed the classification of hyperspectral imagery to be improved. However, nonlinear diffusion results surpassed those obtained using binary partition tree. © The author; licensee Universidad Nacional de Colombia.

Trejos A.,Metropolitan Institute of Technology | Gonzalez D.,National University of Colombia | Ramos-Paja C.A.,National University of Colombia
Energies | Year: 2012

This paper presents modeling approaches for step-up grid-connected photovoltaic systems intended to provide analytical tools for control design. The first approach is based on a voltage source representation of the bulk capacitor interacting with the grid-connected inverter, which is a common model for large DC buses and closed-loop inverters. The second approach considers the inverter of a double-stage PV system as a Norton equivalent, which is widely accepted for open-loop inverters. In addition, the paper considers both ideal and realistic models for the DC/DC converter that interacts with the PV module, providing four mathematical models to cover a wide range of applications. The models are expressed in state space representation to simplify its use in analysis and control design, and also to be easily implemented in simulation software, e.g., Matlab. The PV system was analyzed to demonstrate the non-minimum phase condition for all the models, which is an important aspect to select the control technique. Moreover, the system observability and controllability were studied to define design criteria. Finally, the analytical results are illustrated by means of detailed simulations, and the paper results are validated in an experimental test bench. © 2012 by the authors.

Dario Gomez N.,Metropolitan Institute of Technology | Gomez J.A.,Jaime Isaza Cadavid Colombian Polytechnic
Optics and Lasers in Engineering | Year: 2013

In this work, a technique to improve the dynamical behavior of a non holographic fiber specklegram sensor for measuring high frequency mechanical perturbations is experimentally demonstrated. In these arrangements, the speckle pattern produced by a multimode optical fiber is coupled to an optical fiber of low numerical aperture, which produces a filtering effect that can be used as optical transduction mechanism. In our proposal, the influence of the speckle size on the sensor performance is evaluated by changes in the numerical aperture of the multimode fiber. A strong effect of the near field fiber speckle size on the reproducibility of the mechanical perturbation is found. The behavior of the reproducibility is evaluated by the calculation of the mean of the variance and the correlation between the mechanical and optical normalized signals. © 2013 Elsevier Ltd.

Ponce W.A.,University of Antioquia | Benavides R.H.,University of Antioquia | Benavides R.H.,Metropolitan Institute of Technology
European Physical Journal C | Year: 2011

A way of counting free parameters in the quark mass matrices of the standard model, including the constraints coming from weak basis transformations, is presented; this allows one to understand the exact physical meaning of the parallel and non-parallel texture zeros which appear in some “ansätze” of the 3 × 3 quark mass matrices, including the CP violation phenomena in the analysis; it is shown why the six texture zeros are ruled out. Finally, a five texture zeros “ansatz” which properly copes with all experimental constrains, including the angles of the unitary triangle, is presented. 00A9; Springer-Verlag / Società Italiana di Fisica 2011.

Ponce W.A.,University of Antioquia | Gomez J.D.,University of Antioquia | Benavides R.H.,Metropolitan Institute of Technology
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The phenomenology of the five independent sets of 3×3 quark mass matrices with five texture zeros is carried through in full detail, including predictions for the CP-violation asymmetries. Our study is done without any approximation, first analytically and then numerically. © 2013 American Physical Society.

In 1924, a historically peak time for tuberculosis in Spain, the Ravetllat-Pla Institute was established with the aim of producing and commercializing an anti-tuberculosis serum and researching the variability of the bacteria implicated in this infection. This bacterial form, proposed by Joaquim Ravetllat in the first decade of the 20th century, led to the formulation of a new etiological-pathologic theory of tuberculosis, which upheld the drugs produced by the Institute and was considered heterodox by the official science of the time. The Catalan medical and political network established a space of exclusion leading to the marginalization of the Institute, which, by strengthening its heterodox identity, generated another space of inclusion. In this space, its refuted scientific theory could be socially legitimated and validated through the commercial success of its pharmaceutical products. In this paper, we suggest that the consideration of medicines as commercial products illustrates the active participation of the different users of the Ravetllat-Pla serum in its social construction, re-conceptualization and legitimization. Moreover, from the theoretical framework of inclusion-exclusion dynamics, this research contributes to understanding the processes of knowledge legitimatization by scientific heterodoxy. © 2013, Editorial Universida de Granada. All rights reserved.

Serna E.M.,Metropolitan Institute of Technology
International Journal of Information Management | Year: 2015

Abstract In this article a maturity model for the management of transdisciplinary knowledge is presented, although research nowadays is transdisciplinary the different maturity models proposed in the literature are oriented towards interdisciplinary knowledge management, and, at most, they are oriented toward multidisciplinary knowledge management. The objective is proposing an evolutionary model which accepts knowledge as intensely active and dynamic and evolving in maturity from the early stages of research. But this is possible only if the research team adopt a clear, clean and joint process of disciplinary integration and transdisciplinary integration of the produced and discovered knowledge. In this way, the results of research will have a greater influence on society and they also will be adopted by society. © 2015 Elsevier Ltd.

Roldan-Vasco S.,Metropolitan Institute of Technology
2014 19th Symposium on Image, Signal Processing and Artificial Vision, STSIVA 2014 | Year: 2015

The Deep Brain Stimulation is a surgical procedure in which an electrode is implanted, used by functional neurosurgeons to control the discharge rates of motor units (basal ganglia) in patients with movement disorders. The success of the procedure depends on exactly localization of surgical target, conventionally the subthalamic nucleus, thalamus or globus pallidus internus, which have a particular voltage profile. In this work, two kind of parametric structures, non-linear ARX and linear AR, have been used for modeling the intracerebral signals in patients with Parkinson disease. This work evaluates the fitness with both modeling techniques and their dependence of the linearity regressors and the prediction horizon. The author found that the signals without Gaussian behavior were strongly sensitive of the prediction horizon. On the other hand, both AR and NLARX had good enough precision that guarantees an accurate simulation. This work aims to establish the better modeling criteria trough an a comparison between fitness for AR and NLARX structures and the final model of subthalamic nucleus signals for an oblique coordinate system. © 2014 IEEE.

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